I think we are hitting a high point in the DBZ 
phase...like Pokemon...its prime has past.  The 
Buu saga is a tad long, and don't forget Mr. Satan 
will kill the day and enthusiasm of any die-hard 
DBZ fan.  As far as DBGT, despite a few episodes 
of the Bebi Saga...the series was driven into the 
ground.

I think part of the problem with the DB inflation 
is due to growing access to part-time/one-shot 
buyers via deputy services.  This is not a bad 
thing...more sellers will be lured out by the big 
money...and more cels will be in the market.  This 
means you can't get them all, but you might get 
one or two.

Also, I don't know what you outlokk is like, but 
wise words have been spoken countless times on the 
Forum and that is you really have to limit 
yourself to a few or one character that you really 
like and proceed from there (I too am a 
student...it's tough)...

Lastly, sometimes it helps just to watch the 
videos...that's the reason we collet ... it's the 
anime...I forget sometimes...wasting hours waiting 
for the Taro DBZ update that features Bulma GT 
cels or $1000 Gogeta cels (which sadly was 
purchased...spelling "DOOM" for the rest of us).  
Personally, Gogeta...come-on, weaker than Vegetto 
and dons a silly vest (plus, comes from one of the 
worst DBZ Ovas)...buying for rarity misses the 
point for me, besides that cel is only worth 
$1000.00 if you find another person to buy it (and 
15 minutes on Taro is years in DBZ cel buying 
terms).

Oh, and don't forget the 
genga...cheaper...generally in better condition 
and some are pretty spectacular (better than some 
cels whose lines have faded, etc...)

Anyway...2 cents...on a rainy day in NY